Multi-speed transmission

ABSTRACT

The present disclosure provides a multiple speed transmission having an input member, an output member, a plurality of planetary gearsets, a plurality of interconnecting members and a plurality of torque-transmitting mechanisms. The plurality of planetary gear sets includes first, second and third members. The input member is continuously interconnected with at least one member of one of the plurality of planetary gear sets, and the output member is continuously interconnected with another member of one of the plurality of planetary gear sets. At least eight forward speeds and one reverse speed are achieved by the selective engagement of the five torque-transmitting mechanisms.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 62/068,947, filed Oct. 27, 2014, which is hereby incorporatedby reference in its entirety.

FIELD OF THE DISCLOSURE

The present disclosure relates to a multiple speed transmission, and inparticular to a multiple speed transmission capable of achieving eightor more speeds.

BACKGROUND

Multiple speed transmissions use a number of friction clutches orbrakes, planetary gearsets, shafts, and other elements to achieve aplurality of gear or speed ratios. The architecture, i.e., packaging orlayout of the aforementioned elements, is determined based on cost,size, packaging constraints, and desired ratios. There is a need for newarchitectural designs of multiple speed transmissions for achievingdifferent ratios with improved performance, cost, efficiency,responsiveness, and packaging.

SUMMARY

In one embodiment of the present disclosure, a multiple speedtransmission includes an input member; an output member; first, second,third and fourth planetary gearsets each having first, second and thirdmembers; a plurality of interconnecting members each connected betweenat least one of the first, second, third, and fourth planetary gearsetsand at least another of the first, second, third, and fourth planetarygearsets; a first torque-transmitting mechanism selectively engageableto interconnect the second member of the first planetary gearset with astationary member; a second torque-transmitting mechanism selectivelyengageable to interconnect the first member of the third planetarygearset with the first member of the fourth planetary gearset; a thirdtorque-transmitting mechanism selectively engageable to interconnect thefirst member of the second planetary gearset with the first member ofthe third planetary gearset; a fourth torque-transmitting mechanismselectively engageable to interconnect the first member of the secondplanetary gearset with the second member of the third planetary gearsetand the second member of the fourth planetary gearset; and a fifthtorque-transmitting mechanism selectively engageable to interconnect thesecond member of the first planetary gearset and the third member of thefourth planetary gearset with the first member of the second planetarygearset; wherein the torque transmitting mechanisms are selectivelyengageable in combinations of at least two to establish at least eightforward speed ratios and at least one reverse speed ratio between theinput member and the output member.

In one example of this embodiment, one member of the third planetarygearset is continuously interconnected with the input member and adifferent member of the third planetary gearset is continuouslyinterconnected with the output member. In a second example, the inputmember is continuously interconnected with the first member of the thirdplanetary gearset and the output member is continuously interconnectedwith the second member of the third planetary gearset. In a thirdexample, the plurality of interconnecting members includes a firstinterconnecting member continuously interconnecting the first member ofthe first planetary gearset with the stationary member. In a fourthexample, the plurality of interconnecting members includes a secondinterconnecting member continuously interconnecting the second member ofthe first planetary gearset with the third member of the fourthplanetary gearset.

In a fifth example, the plurality of interconnecting members includes athird interconnecting member continuously interconnecting the thirdmember of the first planetary gearset to the second member of the secondplanetary gearset. In a sixth example, the plurality of interconnectingmembers includes a fourth interconnecting member continuouslyinterconnecting the third member of the second planetary gearset withthe third member of the third planetary gearset. In a seventh example,the plurality of interconnecting members includes a fifthinterconnecting member continuously connected to the first member of thefourth planetary gearset. In an eighth example, the plurality ofinterconnecting members includes a sixth interconnecting membercontinuously connected to the first member of the second planetarygearset. In a ninth example, the first torque-transmitting mechanism isselectively engageable to interconnect the third member of the fourthplanetary gearset with the stationary member.

In another embodiment of this disclosure, a multiple speed transmissionincludes an input member; an output member; first, second, third andfourth planetary gearsets each having a sun gear, a carrier member, anda ring gear, the input member and the output member each beinginterconnected to at least one of the first, second, third, and fourthplanetary gearsets; a first torque-transmitting mechanism selectivelyengageable to interconnect the carrier member of the first planetarygearset and the ring gear of the fourth planetary gearset with astationary member; a second torque-transmitting mechanism selectivelyengageable to interconnect the sun gear of the third planetary gearsetwith the sun gear of the fourth planetary gearset; a thirdtorque-transmitting mechanism selectively engageable to interconnect thesun gear of the second planetary gearset with the sun gear of the thirdplanetary gearset; a fourth torque-transmitting mechanism selectivelyengageable to interconnect the sun gear of the second planetary gearsetwith the carrier member of the third planetary gearset and the carriermember of the fourth planetary gearset; and a fifth torque-transmittingmechanism selectively engageable to interconnect the carrier member ofthe first planetary gearset and the ring gear of the fourth planetarygearset with the sun gear of the second planetary gearset; wherein thetorque transmitting mechanisms are selectively engageable incombinations of at least two to establish at least eight forward speedratios and at least one reverse speed ratio between the input member andthe output member.

In one example of this embodiment, the third planetary gearset iscontinuously interconnected with the input member and the output member.In another example, the input member is continuously interconnected withthe sun gear of the third planetary gearset and the output member iscontinuously interconnected with the carrier member of the thirdplanetary gearset. In a third example, the plurality of interconnectingmembers includes a first interconnecting member continuouslyinterconnecting the sun gear of the first planetary gearset with thestationary member. In a fourth example, the plurality of interconnectingmembers includes a second interconnecting member continuouslyinterconnecting the carrier member of the first planetary gearset withthe ring gear of the fourth planetary gearset.

In a fifth example, the plurality of interconnecting members includes athird interconnecting member continuously interconnecting the ring gearof the first planetary gearset to the carrier member of the secondplanetary gearset. In a sixth example, the plurality of interconnectingmembers includes a fourth interconnecting member continuouslyinterconnecting the ring gear of the second planetary gearset with thering gear of the third planetary gearset. In a seventh example, theplurality of interconnecting members includes a fifth interconnectingmember continuously connected to the sun gear of the fourth planetarygearset. In an eighth example, the plurality of interconnecting membersincludes a sixth interconnecting member continuously connected to thesun gear of the second planetary gearset.

In a different embodiment of the present disclosure, a multiple speedtransmission includes an input member; an output member; first, second,third and fourth planetary gearsets each having a sun gear, a carriermember, and a ring gear, the input member and the output member eachbeing interconnected to at least one of the first, second, third, andfourth planetary gearsets; a first torque-transmitting mechanismselectively engageable to interconnect the carrier member of the firstplanetary gearset and the ring gear of the fourth planetary gearset witha stationary member; a second torque-transmitting mechanism selectivelyengageable to interconnect the sun gear of the third planetary gearsetwith the sun gear of the fourth planetary gearset; a thirdtorque-transmitting mechanism selectively engageable to interconnect thesun gear of the second planetary gearset with the sun gear of the thirdplanetary gearset; a fourth torque-transmitting mechanism selectivelyengageable to interconnect the sun gear of the second planetary gearsetwith the carrier member of the third planetary gearset and the carriermember of the fourth planetary gearset; a fifth torque-transmittingmechanism selectively engageable to interconnect the carrier member ofthe first planetary gearset and the ring gear of the fourth planetarygearset with the sun gear of the second planetary gearset; a firstinterconnecting member of the plurality of interconnecting memberscontinuously interconnecting the sun gear of the first planetary gearsetwith the stationary member; a second interconnecting member of theplurality of interconnecting members continuously interconnecting thecarrier member of the first planetary gearset with the ring gear of thefourth planetary gearset; a third interconnecting member of theplurality of interconnecting members continuously interconnecting thering gear of the first planetary gearset to the carrier member of thesecond planetary gearset; a fourth interconnecting member of theplurality of interconnecting members continuously interconnecting thering gear of the second planetary gearset with the ring gear of thethird planetary gearset; a fifth interconnecting member of the pluralityof interconnecting members continuously connected to the sun gear of thefourth planetary gearset; and a sixth interconnecting member of theplurality of interconnecting members continuously connected to the sungear of the second planetary gearset; wherein the torque transmittingmechanisms are selectively engageable in combinations of at least two toestablish at least eight forward speed ratios and at least one reversespeed ratio between the input member and the output member.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned aspects of the present disclosure and the manner ofobtaining them will become more apparent and the disclosure itself willbe better understood by reference to the following description of theembodiments of the disclosure, taken in conjunction with theaccompanying drawings, wherein:

FIG. 1 is an exemplary block diagram and schematic view of oneillustrative embodiment of a powered vehicular system;

FIG. 2 is a diagrammatic view of an embodiment of a multiple speedtransmission; and

FIG. 3 is a truth table presenting an example of a state of engagementof various torque transmitting mechanisms in each of the availableforward and reverse speeds or gear ratios of the transmissionillustrated in FIG. 2.

Corresponding reference numerals are used to indicate correspondingparts throughout the several views.

DETAILED DESCRIPTION

The embodiments of the present disclosure described below are notintended to be exhaustive or to limit the disclosure to the preciseforms disclosed in the following detailed description. Rather, theembodiments are chosen and described so that others skilled in the artmay appreciate and understand the principles and practices of thepresent disclosure.

Referring now to FIG. 1, a block diagram and schematic view of oneillustrative embodiment of a vehicular system 100 having a drive unit102 and transmission 118 is shown. In the illustrated embodiment, thedrive unit 102 may include an internal combustion engine, diesel engine,electric motor, or other power-generating device. The drive unit 102 isconfigured to rotatably drive an output shaft 104 that is coupled to aninput or pump shaft 106 of a conventional torque converter 108. Theinput or pump shaft 106 is coupled to an impeller or pump 110 that isrotatably driven by the output shaft 104 of the drive unit 102. Thetorque converter 108 further includes a turbine 112 that is coupled to aturbine shaft 114, and the turbine shaft 114 is coupled to, or integralwith, a rotatable input shaft 124 of the transmission 118. Thetransmission 118 can also include an internal pump 120 for buildingpressure within different flow circuits (e.g., main circuit, lubecircuit, etc.) of the transmission 118. The pump 120 can be driven by ashaft 116 that is coupled to the output shaft 104 of the drive unit 102.In this arrangement, the drive unit 102 can deliver torque to the shaft116 for driving the pump 120 and building pressure within the differentcircuits of the transmission 118.

The transmission 118 can include a planetary gear system 122 having anumber of automatically selected gears. An output shaft 126 of thetransmission 118 is coupled to or integral with, and rotatably drives, apropeller shaft 128 that is coupled to a conventional universal joint130. The universal joint 130 is coupled to, and rotatably drives, anaxle 132 having wheels 134A and 134B mounted thereto at each end. Theoutput shaft 126 of the transmission 118 drives the wheels 134A and 134Bin a conventional manner via the propeller shaft 128, universal joint130 and axle 132.

A conventional lockup clutch 136 is connected between the pump 110 andthe turbine 112 of the torque converter 108. The operation of the torqueconverter 108 is conventional in that the torque converter 108 isoperable in a so-called “torque converter” mode during certain operatingconditions such as vehicle launch, low speed and certain gear shiftingconditions. In the torque converter mode, the lockup clutch 136 isdisengaged and the pump 110 rotates at the rotational speed of the driveunit output shaft 104 while the turbine 112 is rotatably actuated by thepump 110 through a fluid (not shown) interposed between the pump 110 andthe turbine 112. In this operational mode, torque multiplication occursthrough the fluid coupling such that the turbine shaft 114 is exposed todrive more torque than is being supplied by the drive unit 102, as isknown in the art. The torque converter 108 is alternatively operable ina so-called “lockup” mode during other operating conditions, such aswhen certain gears of the planetary gear system 122 of the transmission118 are engaged. In the lockup mode, the lockup clutch 136 is engagedand the pump 110 is thereby secured directly to the turbine 112 so thatthe drive unit output shaft 104 is directly coupled to the input shaft124 of the transmission 118, as is also known in the art.

The transmission 118 further includes an electro-hydraulic system 138that is fluidly coupled to the planetary gear system 122 via a number,J, of fluid paths, 140 ₁-140 _(J), where J may be any positive integer.The electro-hydraulic system 138 is responsive to control signals toselectively cause fluid to flow through one or more of the fluid paths,140 ₁-140 _(J), to thereby control operation, i.e., engagement anddisengagement, of a plurality of corresponding friction devices in theplanetary gear system 122. The plurality of friction devices mayinclude, but are not limited to, one or more conventional brake devices,one or more torque transmitting devices, and the like. Generally, theoperation, i.e., engagement and disengagement, of the plurality offriction devices is controlled by selectively controlling the frictionapplied by each of the plurality of friction devices, such as bycontrolling fluid pressure to each of the friction devices. In oneexample embodiment, which is not intended to be limiting in any way, theplurality of friction devices include a plurality of brake and torquetransmitting devices in the form of conventional clutches that may eachbe controllably engaged and disengaged via fluid pressure supplied bythe electro-hydraulic system 138. In any case, changing or shiftingbetween the various gears of the transmission 118 is accomplished in aconventional manner by selectively controlling the plurality of frictiondevices via control of fluid pressure within the number of fluid paths140 ₁-140 _(J).

The system 100 further includes a transmission control circuit 142 thatcan include a memory unit 144. The transmission control circuit 142 isillustratively microprocessor-based, and the memory unit 144 generallyincludes instructions stored therein that are executable by a processorof the transmission control circuit 142 to control operation of thetorque converter 108 and operation of the transmission 118, i.e.,shifting between the various gears of the planetary gear system 122. Itwill be understood, however, that this disclosure contemplates otherembodiments in which the transmission control circuit 142 is notmicroprocessor-based, but is configured to control operation of thetorque converter 108 and/or transmission 118 based on one or more setsof hardwired instructions and/or software instructions stored in thememory unit 144.

In the system 100 illustrated in FIG. 1, the torque converter 108 andthe transmission 118 include a number of sensors configured to producesensor signals that are indicative of one or more operating states ofthe torque converter 108 and transmission 118, respectively. Forexample, the torque converter 108 illustratively includes a conventionalspeed sensor 146 that is positioned and configured to produce a speedsignal corresponding to the rotational speed of the pump shaft 106,which is the same rotational speed of the output shaft 104 of the driveunit 102. The speed sensor 146 is electrically connected to a pump speedinput, PS, of the transmission control circuit 142 via a signal path152, and the transmission control circuit 142 is operable to process thespeed signal produced by the speed sensor 146 in a conventional mannerto determine the rotational speed of the pump shaft 106/drive unitoutput shaft 104.

The transmission 118 illustratively includes another conventional speedsensor 148 that is positioned and configured to produce a speed signalcorresponding to the rotational speed of the transmission input shaft124, which is the same rotational speed as the turbine shaft 114. Theinput shaft 124 of the transmission 118 is directly coupled to, orintegral with, the turbine shaft 114, and the speed sensor 148 mayalternatively be positioned and configured to produce a speed signalcorresponding to the rotational speed of the turbine shaft 114. In anycase, the speed sensor 148 is electrically connected to a transmissioninput shaft speed input, TIS, of the transmission control circuit 142via a signal path 154, and the transmission control circuit 142 isoperable to process the speed signal produced by the speed sensor 148 ina conventional manner to determine the rotational speed of the turbineshaft 114/transmission input shaft 124.

The transmission 118 further includes yet another speed sensor 150 thatis positioned and configured to produce a speed signal corresponding tothe rotational speed of the output shaft 126 of the transmission 118.The speed sensor 150 may be conventional, and is electrically connectedto a transmission output shaft speed input, TOS, of the transmissioncontrol circuit 142 via a signal path 156. The transmission controlcircuit 142 is configured to process the speed signal produced by thespeed sensor 150 in a conventional manner to determine the rotationalspeed of the transmission output shaft 126.

In the illustrated embodiment, the transmission 118 further includes oneor more actuators configured to control various operations within thetransmission 118. For example, the electro-hydraulic system 138described herein illustratively includes a number of actuators, e.g.,conventional solenoids or other conventional actuators, that areelectrically connected to a number, J, of control outputs, CP₁-CP_(J),of the transmission control circuit 142 via a corresponding number ofsignal paths 72 ₁-72 _(J), where J may be any positive integer asdescribed above. The actuators within the electro-hydraulic system 138are each responsive to a corresponding one of the control signals,CP₁-CP_(J), produced by the transmission control circuit 142 on one ofthe corresponding signal paths 72 ₁-72 _(J) to control the frictionapplied by each of the plurality of friction devices by controlling thepressure of fluid within one or more corresponding fluid passageway 140₁-140 _(J), and thus control the operation, i.e., engaging anddisengaging, of one or more corresponding friction devices, based oninformation provided by the various speed sensors 146, 148, and/or 150.

The friction devices of the planetary gear system 122 are illustrativelycontrolled by hydraulic fluid which is distributed by theelectro-hydraulic system in a conventional manner. For example, theelectro-hydraulic system 138 illustratively includes a conventionalhydraulic positive displacement pump (not shown) which distributes fluidto the one or more friction devices via control of the one or moreactuators within the electro-hydraulic system 138. In this embodiment,the control signals, CP₁-CP_(J), are illustratively analog frictiondevice pressure commands to which the one or more actuators areresponsive to control the hydraulic pressure to the one or morefrictions devices. It will be understood, however, that the frictionapplied by each of the plurality of friction devices may alternativelybe controlled in accordance with other conventional friction devicecontrol structures and techniques, and such other conventional frictiondevice control structures and techniques are contemplated by thisdisclosure. In any case, however, the analog operation of each of thefriction devices is controlled by the control circuit 142 in accordancewith instructions stored in the memory unit 144.

In the illustrated embodiment, the system 100 further includes a driveunit control circuit 160 having an input/output port (I/O) that iselectrically coupled to the drive unit 102 via a number, K, of signalpaths 162, wherein K may be any positive integer. The drive unit controlcircuit 160 may be conventional, and is operable to control and managethe overall operation of the drive unit 102. The drive unit controlcircuit 160 further includes a communication port, COM, which iselectrically connected to a similar communication port, COM, of thetransmission control circuit 142 via a number, L, of signal paths 164,wherein L may be any positive integer. The one or more signal paths 164are typically referred to collectively as a data link. Generally, thedrive unit control circuit 160 and the transmission control circuit 142are operable to share information via the one or more signal paths 164in a conventional manner. In one embodiment, for example, the drive unitcontrol circuit 160 and transmission control circuit 142 are operable toshare information via the one or more signal paths 164 in the form ofone or more messages in accordance with a society of automotiveengineers (SAE) J-1939 communications protocol, although this disclosurecontemplates other embodiments in which the drive unit control circuit160 and the transmission control circuit 142 are operable to shareinformation via the one or more signal paths 164 in accordance with oneor more other conventional communication protocols (e.g., from aconventional databus such as J1587 data bus, J1939 data bus, IESCAN databus, GMLAN, Mercedes PT-CAN).

Referring to FIG. 2, a schematic representation or stick diagramillustrates one embodiment of a multi-speed transmission 200 accordingto the present disclosure. The transmission 200 includes an input shaft202 and an output shaft 204. The input shaft 202 and output shaft 204can be disposed along the same axis or centerline of the transmission200. In another aspect, the different shafts can be disposed alongdifferent axes or centerlines. In a further aspect, the different shaftscan be disposed parallel to one another, but along different axes orcenterlines. Other aspect can be appreciated by one skilled in the art.

The transmission 200 can also include a plurality of planetary gearsets.In the illustrated embodiment of FIG. 2, the transmission 200 includes afirst planetary gearset 206, a second planetary gearset 208, a thirdplanetary gearset 210, and a fourth planetary gearset 212. Eachplanetary gearset can be referred to as a simple or compound planetarygearset. For example, in some aspects, one or more of the plurality ofplanetary gearsets can be formed as an idler planetary gearset. In FIG.2, however, each of the planetary gearsets is represented as being asimple planetary gearset.

One or more of the plurality of planetary gearsets can be arranged indifferent locations within the transmission 200, but for sake ofsimplicity and in this particular example only, the planetary gearsetsare aligned in an axial direction consecutively in sequence (i.e.,first, second, third, and fourth between the input and output shafts).

The transmission 200 may also include a plurality of torque-transmittingor gearshifting mechanisms. For example, one or more of these mechanismscan include a clutch or brake. In one aspect, each of the plurality ofmechanisms is disposed within an outer housing of the transmission 200.In another aspect, however, one or more of the mechanisms may bedisposed outside of the housing. Each of the plurality of mechanisms canbe coupled to one or more of the plurality of planetary gearsets, whichwill be described further below.

In the embodiment of FIG. 2, the transmission 200 can include a firsttorque-transmitting mechanism 258 that is configured to function as abrake (e.g., the torque-transmitting mechanism is fixedly coupled to theouter housing of the transmission 200). The brake can be configured as ashiftable-friction-locked disk brake, shiftable friction-locked bandbrake, shiftable form-locking claw or conical brake, or any other typeof known brake. The transmission 200 can include a secondtorque-transmitting mechanism 260, a third torque-transmitting mechanism262, a fourth torque-transmitting mechanism 264, and a fifthtorque-transmitting mechanism 266 that are configured to function asclutches. These can be shiftable friction-locked multi-disk clutches,shiftable form-locking claw or conical clutches, wet clutches, or anyother known form of a clutch. With these five torque-transmittingmechanisms, selective shifting of at least eight forward gears and atleast one reverse gear is possible.

The transmission 200 of FIG. 2 may also include up to eight differentshafts, which is inclusive of the input shaft 202 and output shaft 204.Each of these shafts, designated as a first shaft 222, a second shaft224, a third shaft 226, a fourth shaft 236, a fifth shaft 246, and asixth shaft 248, are configured to be connected to one or more of theplurality of planetary gearsets or plurality of torque-transmittingmechanism between the input shaft 202 and output shaft 204.

In FIG. 2, the first planetary gearset 206 can include a first sun gear214, a first ring gear 216, and a first carrier member 218 thatrotatably supports a set of pinion gears 220. The second planetarygearset 208 can include a second sun gear 228, a second ring gear 230,and a second carrier member 232 that rotatably supports a set of piniongears 234. The third planetary gearset 210 can include a third sun gear238, a third ring gear 240, and a third carrier member 242 thatrotatably supports a set of pinion gears 244. The fourth planetarygearset 212 can include a fourth sun gear 250, a fourth ring gear 252,and a fourth carrier member 254 that rotatably supports a set of piniongears 256.

The transmission 200 is capable of transferring torque from the inputshaft 202 to the output shaft 204 in at least eight forward gears orratios and at least one reverse gear or ratio. Each of the forwardtorque ratios and the reverse torque ratios can be attained by theselective engagement of one or more of the torque-transmittingmechanisms (i.e., torque-transmitting mechanisms 258, 260, 262, 264, and266). Those skilled in the art will readily understand that a differentspeed ratio is associated with each torque ratio. Thus, at least eightforward speed ratios and at least one reverse speed ratio may beattained by transmission 200. An example of the gear ratios that may beobtained using the embodiments of the present disclosure are also shownin FIG. 3. Of course, other gear ratios are achievable depending on thegear diameter, gear tooth count and gear configuration selected.

As for the transmission 200, kinematic coupling of the first planetarygearset 206 is shown in FIG. 2. The first sun gear 214 is coupled to thefirst shaft 222, which is directly connected to the transmission case.The first ring gear 216 is coupled to the third shaft 226 for commonrotation therewith. First pinion gears 220 are configured to intermeshwith the first sun gear 214 and first ring gear 216. First carriermember 218 is coupled for common rotation with the second shaft 224.

With respect to the second planetary gearset 208, the second sun gear228 is coupled to the sixth shaft 248 for common rotation therewith. Thesecond ring gear 230 is coupled to the third shaft 236 for commonrotation therewith. Second pinion gears 234 are configured to intermeshwith the second sun gear 228 and second ring gear 230, and the secondcarrier member 232 is coupled for common rotation with the third shaft236. Thus, the second carrier member 232 is coupled to the first ringgear 226 for common rotation therewith.

The third sun gear 238 of the third planetary gearset 210 is coupled tothe input shaft 202 for common rotation therewith. The third ring gear240 is coupled to the fourth shaft 236, and hence the second ring gear230, for common rotation therewith. Third pinion gears are configured tointermesh with the third sun gear 238 and third ring gear 240, and thethird carrier member 242 is coupled for common rotation with the outputshaft 204.

The kinematic relationship of the fourth planetary gearset 212 is suchthat the fourth sun gear 250 is coupled to the fifth shaft 246 forcommon rotation therewith. The fourth ring gear 252 is coupled to thesecond shaft 224, and hence the first carrier member 218, for commonrotation therewith. The fourth pinion gears 256 are configured tointermesh with the fourth sun gear 250 and the fourth ring gear 252. Thefourth carrier member 254 is coupled to the output shaft 204 and thirdcarrier member 242 for common rotation therewith.

With regards to the kinematic coupling of the five torque-transmittingmechanisms to the previously described shafts, the multiple speedtransmission 200 of FIG. 2 provides that the first torque-transmittingmechanism 258 is arranged within the power flow between the second shaft224 and the housing G of the transmission 200. In this manner, the firsttorque-transmitting mechanism 258 is configured to act as a brake. Thesecond torque-transmitting mechanism 260 is arranged within the powerflow between the input shaft 202 and the fifth shaft 246. Thus, thesecond torque-transmitting mechanism 260 is configured to act as aclutch. In this embodiment of the transmission 200 therefore one of thefive torque-transmitting mechanisms is configured to act as a brake andthe other four torque-transmitting mechanisms are configured to act asclutches.

The third torque-transmitting mechanism 262, for example, is arrangedwithin the power flow between the input shaft 202 and the sixth shaft248. The fourth torque-transmitting mechanism 264 is arranged within thepower flow between the sixth shaft 248 and the output shaft 204.Moreover, the fifth torque-transmitting mechanism 266 is arranged withinthe power flow between the second shaft 224 and the sixth shaft 248.

The kinematic couplings of the embodiment in FIG. 2 can further bedescribed with respect to the selective engagement of thetorque-transmitting mechanisms with respect to one or more components ofthe plurality of planetary gearsets. For example, in the transmission200, the first torque-transmitting mechanism 258 is selectivelyengageable to couple the first carrier member 218, the fourth ring gear252, and the second shaft 224 to the housing G of the transmission 200.The second torque-transmitting mechanism 260 is selectively engageableto couple the third sun gear 238 and the input shaft 202 to the fifthshaft 246 and the fourth sun gear 250. Moreover, the thirdtorque-transmitting mechanism 262 is selectively engageable to couplethe third sun gear 238 and the input shaft 202 to the sixth shaft 248and second sun gear 250. The fourth torque-transmitting mechanism 264 isselectively engageable to couple the second sun gear 228 and sixth shaft248 to the third carrier member 244, the fourth carrier member 254, andthe output shaft 204. Lastly, the fifth torque-transmitting mechanism266 is selectively engageable to couple the first carrier member 218,the fourth ring gear 252, and the second shaft 224 to the second sungear 228 and the sixth shaft 248.

As previously described, the aforementioned embodiment is capable oftransmitting torque from a respective input shaft to a respective outputshaft in at least eight forward torque ratios and one reverse torqueratio. Referring to FIG. 3, one example of a truth table is shownrepresenting a state of engagement of various torque transmittingmechanisms in each of the available forward and reverse speeds or gearratios of the transmission illustrated in FIG. 2. It is to be understoodthat FIG. 3 is only one example of any number of truth tables possiblefor achieving at least eight forward ratios and one reverse ratio, andone skilled in the art is capable of configuring diameters, gear toothcounts, and gear configurations to achieve other ratios.

In the example of FIG. 3, the reverse ratio (Rev) can be achieved by theselective engagement of the torque-transmitting mechanisms as set forthin the table. As shown, the first torque transmitting mechanism (C1) andthird torque-transmitting mechanism (C3) are selectively engaged toestablish the reverse ratio. Thus, in transmission 200 of FIG. 2, theselective engagement of mechanisms 258 and 262 can establish the reverseratio.

In neutral (Neu), none of the torque-transmitting mechanisms carrytorque. One or more of the torque-transmitting mechanisms, however, maybe engaged in neutral but not carrying torque. For example, the firsttorque-transmitting mechanism can be engaged in neutral, therebyresulting in the third torque-transmitting mechanism being disengagedbetween a shift between the one reverse ratio and neutral.

A first forward ratio (shown as 1st) in the table of FIG. 3 is achievedby engaging the brake and one of the clutches. In FIG. 2, for example,the first torque-transmitting mechanism 258 and the fourthtorque-transmitting mechanism 264 are engaged. Thus, when transitioningbetween neutral and the first forward range, the firsttorque-transmitting mechanism may already be engaged, and the fourthtorque-transmitting mechanism is selectively engaged.

In a second or subsequent forward ratio, indicated as 2nd in FIG. 3, thefirst torque-transmitting mechanism and the fifth torque-transmittingmechanism are selectively engaged. Therefore, when transitioning betweenthe first forward ratio and the second forward ratio, the fourthtorque-transmitting mechanism is released and the fifthtorque-transmitting mechanism is engaged.

In a third or subsequent forward ratio, indicated as 3rd forward ratioin FIG. 3, the first torque-transmitting mechanism and secondtorque-transmitting mechanism are engaged. To transition from the secondforward ratio to the third forward ratio, for example, the fifthtorque-transmitting mechanism is released and the secondtorque-transmitting mechanism is engaged.

In a fourth or the next subsequent forward ratio, indicated as 4th inFIG. 3, the second torque-transmitting mechanism and fifthtorque-transmitting mechanism are engaged. Thus, to transition from thethird forward ratio and upshift to the fourth forward ratio, the firsttorque-transmitting mechanism is released and the fifthtorque-transmitting mechanism is engaged.

In a fifth or the next subsequent forward ratio, indicated as 5th inFIG. 3, the second torque-transmitting mechanism and fourthtorque-transmitting mechanism are selectively engaged. Thus, totransition from the fourth forward ratio and upshift to the fifthforward ratio, the fifth torque-transmitting mechanism is released andthe fourth torque-transmitting mechanism is engaged.

In a sixth or the next subsequent forward ratio, indicated as 6th inFIG. 3, the second torque-transmitting mechanism and thirdtorque-transmitting mechanism are engaged. Thus, to transition from thefifth forward ratio and upshift to the sixth forward ratio, the fourthtorque-transmitting mechanism is released and the thirdtorque-transmitting mechanism is engaged.

In a seventh or the next subsequent forward ratio, indicated as 7th inFIG. 3, the third torque-transmitting mechanism and the fourthtorque-transmitting mechanism are engaged. Thus, to transition from thesixth forward ratio and upshift to the seventh forward ratio, the secondtorque-transmitting mechanism is released and the fourthtorque-transmitting mechanism is engaged.

In an eighth or the next subsequent forward ratio, indicated as 8th inFIG. 3, the third torque-transmitting mechanism and fifthtorque-transmitting mechanism are engaged. Thus, to transition from theseventh forward ratio and upshift to the eighth forward ratio, thefourth torque-transmitting mechanism is released and the fifthtorque-transmitting mechanism is engaged.

The present disclosure contemplates that downshifts follow the reversesequence of the corresponding upshift (as described above), and severalpower-on skip-shifts that are single-transition are possible (e.g. from1st to 3rd or 3rd to 1st).

While exemplary embodiments incorporating the principles of the presentdisclosure have been disclosed hereinabove, the present disclosure isnot limited to the disclosed embodiments. Instead, this application isintended to cover any variations, uses, or adaptations of the disclosureusing its general principles. Further, this application is intended tocover such departures from the present disclosure as come within knownor customary practice in the art to which this disclosure pertains andwhich fall within the limits of the appended claims.

1. A multiple speed transmission, comprising: an input member; an outputmember; first, second, third and fourth planetary gearsets each havingfirst, second and third members; a plurality of interconnecting memberseach connected between at least one of the first, second, third, andfourth planetary gearsets and at least another of the first, second,third, and fourth planetary gearsets; a first torque-transmittingmechanism selectively engageable to interconnect the second member ofthe first planetary gearset with a stationary member; a secondtorque-transmitting mechanism selectively engageable to interconnect thefirst member of the third planetary gearset with the first member of thefourth planetary gearset; a third torque-transmitting mechanismselectively engageable to interconnect the first member of the secondplanetary gearset with the first member of the third planetary gearset;a fourth torque-transmitting mechanism selectively engageable tointerconnect the first member of the second planetary gearset with thesecond member of the third planetary gearset and the second member ofthe fourth planetary gearset; and a fifth torque-transmitting mechanismselectively engageable to interconnect the second member of the firstplanetary gearset and the third member of the fourth planetary gearsetwith the first member of the second planetary gearset; wherein thetorque transmitting mechanisms are selectively engageable incombinations of at least two to establish at least eight forward speedratios and at least one reverse speed ratio between the input member andthe output member.
 2. The multiple speed transmission of claim 1,wherein one member of the third planetary gearset is continuouslyinterconnected with the input member and a different member of the thirdplanetary gearset is continuously interconnected with the output member.3. The multiple speed transmission of claim 2, wherein the input memberis continuously interconnected with the first member of the thirdplanetary gearset and the output member is continuously interconnectedwith the second member of the third planetary gearset.
 4. The multiplespeed transmission of claim 1, wherein the plurality of interconnectingmembers includes a first interconnecting member continuouslyinterconnecting the first member of the first planetary gearset with thestationary member.
 5. The multiple speed transmission of claim 1,wherein the plurality of interconnecting members includes a secondinterconnecting member continuously interconnecting the second member ofthe first planetary gearset with the third member of the fourthplanetary gearset.
 6. The multiple speed transmission of claim 1,wherein the plurality of interconnecting members includes a thirdinterconnecting member continuously interconnecting the third member ofthe first planetary gearset to the second member of the second planetarygearset.
 7. The multiple speed transmission of claim 1, wherein theplurality of interconnecting members includes a fourth interconnectingmember continuously interconnecting the third member of the secondplanetary gearset with the third member of the third planetary gearset.8. The multiple speed transmission of claim 1, wherein the plurality ofinterconnecting members includes a fifth interconnecting membercontinuously connected to the first member of the fourth planetarygearset.
 9. The multiple speed transmission of claim 1, wherein theplurality of interconnecting members includes a sixth interconnectingmember continuously connected to the first member of the secondplanetary gearset.
 10. The multiple speed transmission of claim 1,wherein the first torque-transmitting mechanism is selectivelyengageable to interconnect the third member of the fourth planetarygearset with the stationary member.
 11. A multiple speed transmission,comprising: an input member; an output member; first, second, third andfourth planetary gearsets each having a sun gear, a carrier member, anda ring gear, the input member and the output member each beinginterconnected to at least one of the first, second, third, and fourthplanetary gearsets; a first torque-transmitting mechanism selectivelyengageable to interconnect the carrier member of the first planetarygearset and the ring gear of the fourth planetary gearset with astationary member; a second torque-transmitting mechanism selectivelyengageable to interconnect the sun gear of the third planetary gearsetwith the sun gear of the fourth planetary gearset; a thirdtorque-transmitting mechanism selectively engageable to interconnect thesun gear of the second planetary gearset with the sun gear of the thirdplanetary gearset; a fourth torque-transmitting mechanism selectivelyengageable to interconnect the sun gear of the second planetary gearsetwith the carrier member of the third planetary gearset and the carriermember of the fourth planetary gearset; and a fifth torque-transmittingmechanism selectively engageable to interconnect the carrier member ofthe first planetary gearset and the ring gear of the fourth planetarygearset with the sun gear of the second planetary gearset; wherein thetorque transmitting mechanisms are selectively engageable incombinations of at least two to establish at least eight forward speedratios and at least one reverse speed ratio between the input member andthe output member.
 12. The multiple speed transmission of claim 11,wherein the third planetary gearset is continuously interconnected withthe input member and the output member.
 13. The multiple speedtransmission of claim 12, wherein the input member is continuouslyinterconnected with the sun gear of the third planetary gearset and theoutput member is continuously interconnected with the carrier member ofthe third planetary gearset.
 14. The multiple speed transmission ofclaim 11, wherein the plurality of interconnecting members includes afirst interconnecting member continuously interconnecting the sun gearof the first planetary gearset with the stationary member.
 15. Themultiple speed transmission of claim 11, wherein the plurality ofinterconnecting members includes a second interconnecting membercontinuously interconnecting the carrier member of the first planetarygearset with the ring gear of the fourth planetary gearset.
 16. Themultiple speed transmission of claim 11, wherein the plurality ofinterconnecting members includes a third interconnecting membercontinuously interconnecting the ring gear of the first planetarygearset to the carrier member of the second planetary gearset.
 17. Themultiple speed transmission of claim 11, wherein the plurality ofinterconnecting members includes a fourth interconnecting membercontinuously interconnecting the ring gear of the second planetarygearset with the ring gear of the third planetary gearset.
 18. Themultiple speed transmission of claim 11, wherein the plurality ofinterconnecting members includes a fifth interconnecting membercontinuously connected to the sun gear of the fourth planetary gearset.19. The multiple speed transmission of claim 11, wherein the pluralityof interconnecting members includes a sixth interconnecting membercontinuously connected to the sun gear of the second planetary gearset.20. A multiple speed transmission, comprising: an input member; anoutput member; first, second, third and fourth planetary gearsets eachhaving a sun gear, a carrier member, and a ring gear, the input memberand the output member each being interconnected to at least one of thefirst, second, third, and fourth planetary gearsets; a firsttorque-transmitting mechanism selectively engageable to interconnect thecarrier member of the first planetary gearset and the ring gear of thefourth planetary gearset with a stationary member; a secondtorque-transmitting mechanism selectively engageable to interconnect thesun gear of the third planetary gearset with the sun gear of the fourthplanetary gearset; a third torque-transmitting mechanism selectivelyengageable to interconnect the sun gear of the second planetary gearsetwith the sun gear of the third planetary gearset; a fourthtorque-transmitting mechanism selectively engageable to interconnect thesun gear of the second planetary gearset with the carrier member of thethird planetary gearset and the carrier member of the fourth planetarygearset; a fifth torque-transmitting mechanism selectively engageable tointerconnect the carrier member of the first planetary gearset and thering gear of the fourth planetary gearset with the sun gear of thesecond planetary gearset; a first interconnecting member of theplurality of interconnecting members continuously interconnecting thesun gear of the first planetary gearset with the stationary member; asecond interconnecting member of the plurality of interconnectingmembers continuously interconnecting the carrier member of the firstplanetary gearset with the ring gear of the fourth planetary gearset; athird interconnecting member of the plurality of interconnecting memberscontinuously interconnecting the ring gear of the first planetarygearset to the carrier member of the second planetary gearset; a fourthinterconnecting member of the plurality of interconnecting memberscontinuously interconnecting the ring gear of the second planetarygearset with the ring gear of the third planetary gearset; a fifthinterconnecting member of the plurality of interconnecting memberscontinuously connected to the sun gear of the fourth planetary gearset;and a sixth interconnecting member of the plurality of interconnectingmembers continuously connected to the sun gear of the second planetarygearset; wherein the torque transmitting mechanisms are selectivelyengageable in combinations of at least two to establish at least eightforward speed ratios and at least one reverse speed ratio between theinput member and the output member.